1. Field of the Invention
The invention relates to needle bar zig-zag mechanism for use in a sewing machine.
2. Description of the Prior Art
It has been a common practice in sewing machines to mount a needle bar for endwise reciprocation in an upper and a lower spherical bearing, and for the upper bearing to be carried in a gate which was pivoted on a foot presser bar for actuated movements resulting in zig-zag motion of a needle attached to the lower end of the needle bar. Actuating forces had to be applied to the gate at a point closer to its pivotal axis than was desireable because of the limited amount of space available in the machine. The actuating forces therefor had to be rather large, and a gate of substantial mass which further added to the force requirements had to be utilized to stabilize the operation of the needle bar as required to prevent excessive vibration of the needle.